[ci-skip] Update README with examples

README.md

@@ -10,6 +10,51 @@ See: https://www.chromestatus.com/features/4805872211460096
 
 [![sauce labs test status][sauce-badge]][sauce-href]
 
+## Install
+
+```bash
+npm i browser-unhandled-rejection
+```
+or
+```bash
+yarn add browser-unhandled-rejection
+```
+
+## Usage
+### Automatic polyfill
+This automatically applies the polyfill to the global `Promise` object if it is needed.
+```js
+import {auto} from 'browser-unhandled-rejection';
+
+auto(); // Applies polyfill if necessary to window.Promise
+```
+
+### Manual polyfill
+The following snippet is equivalent to `auto()`:
+```js
+import {polyfill} from 'browser-unhandled-rejection';
+
+if (typeof PromiseRejectionEvent !== 'undefined') {
+  polyfill(); // Polyfills window.Promise
+}
+```
+
+### Ponyfill
+This may may useful if you don't want to mutate `window.Promise`:
+```js
+import MyPromise from 'browser-unhandled-rejection';
+
+window.addEventListener('unhandledrejection', () => {
+  console.log('unhandledrejection was triggered');
+});
+
+MyPromise.reject('will trigger unhandledrejection event');
+
+new MyPromise((resolve, reject) => {
+  reject('will also trigger unhandledrejection event');
+});
+```
+
 [npm-badge]: https://badge.fury.io/js/browser-unhandled-rejection.svg
 [npm-href]: https://www.npmjs.com/package/browser-unhandled-rejection
 [build-badge]: https://travis-ci.org/rtsao/browser-unhandled-rejection.svg?branch=master